The present invention relates generally to magnetic devices for electronic circuits and associated methods of assembly and more particularly to stacked core devices for providing a middle core leg with a stepped end profile and associated methods for assembling stacked step gap core components.
Magnetic components for electronic circuits, including inductors and transformers, are known in the art. Some conventional step gap inductors and transformers include a category of magnetic components that provide a stepped air gap, or an air gap having a stepped profile, defined between opposing legs of a magnetic flux loop. The stepped air gap provides improved performance of the core apparatus and the magnetic component that includes the core.
Conventional core devices including a stepped air gap commonly use a first, non-stepped E-core positioned opposite a second E-core including a middle leg having a stepped end profile. The first, non-stepped E-core includes a middle leg extending toward the middle leg of the second E-core, and a stepped gap is defined between the distal ends of the two middle legs. The stepped gap includes two widths corresponding to the stepped profile of the middle leg on the second E-core. For example, U.S. Patent Publication No. 2010/00852138 illustrates a conventional core device including first and second opposing E-cores defining a vertical stepped gap between the middle legs of the two E-cores.
One problem associated with conventional step gap core devices and associated magnetic components such as inductors and transformers includes the expense, difficulty and unreliability of manufacture. The step gap profile in conventional step gap inductors and transformers is generally formed by grinding the desired stepped profile into the distal end of the middle leg of one of the E-cores.
Conventional methods of grinding step gap core assemblies for inductors and transformers is problematic because it is difficult to accurately and consistently grind a specific dimension step gap on a ferrite core. The step gap includes horizontal and vertical dimensions that must be accurately maintained to ensure proper performance of the magnetic component. Additionally, in a manufacturing environment wherein numerous core devices are produced, cores must be consistently ground to the same dimensional tolerances to ensure consistent performance between magnetic devices that include the ground cores. However, the conventional grinding process leads to large dimensional tolerance ranges which adversely affect component performance and reliability. When the dimensions of the step gap are not precise, undesirable variability in performance of the magnetic components results.
What is needed then are improvements in step gap cores, magnetic components utilizing step gap cores and methods of manufacturing magnetic step gap cores and components having step gap cores.